It is widely known that Ashoka was a follower of Buddhism and that the Ashokan Dhamma — as reflects from his inscriptions — has many Buddhist beliefs. However, it has its roots in the Vedic-Upanishadic tradition; Whose message up to the time of Ashoka has been transferred from lavish rituals to leading a holy and simple life.
Ashoka openly declared that he was a follower of Buddhism. He famously hosted the Third Buddhist Council. In Ashokan Dhamma, the Buddhist message of non-violence (non-violence) comes up again and again.
Rock edit 1 announces a ban on animal sacrifice. However, we should not think that this was a very Buddhist doctrine; In fact, key elements of Buddhism such as the eight-fold path, nirvana (enlightenment), the doctrine of impermanence, the laws of the causative origination, etc. are completely missing from inscriptions. In fact, Ashoka’s message had deep roots at the core.
In the Vedic tradition, tolerance has been emphasized.
The Rigveda says, "Ekam dukh vipra bahudha vadanti", which means a truth but the sages speak it differently.
Similarly, in Rock Edit 12, Ashoka instructs people to respect both Brahmins and Shamans.
Similarly, the Upanishads emphasize the true meaning of spirituality. They talk about good works and humility, e.g. Story of Nachiket from Katha Upanishad.
Ashoka’s inscription also focuses on the moral life. Therefore, we can say that Ashoka’s Dhamma was rooted in the Vedic-Upanishadic tradition because it reflects a similar message without mentioning specific principles.